<template>
  <div class="goods">
    <div class="menu-wrapper" ref="menuWrapper">
      <ul>
        <!--当前menu的索引值对应的是区间内的索引值-->
        <li v-for="(item,index) in goods" class="menu-item" :class="{'current':currentIndex===index}" @click="selectMenu(index,$event)">
          <span class="text">
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>{{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" ref="foodsWrapper">
      <ul>
        <!--菜品类-->
        <li v-for="item in goods" class="food-list food-list-hook">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <!--每类菜品的菜-->
            <li @click.stop="selectFood(food,$event)" v-for="food in item.foods" class="food-item">
              <div class="icon">
                <img :src="food.icon" alt="">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span>月售{{food.sellCount}}份</span>
                  <span>好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">￥{{food.price}}元</span>
                  <span v-show="food.oldPrice" class="old">{{food.oldPrice}}元</span>
                </div>
                <div class="cartcontrol-wrapper">
                  <!--父元素监听子元素的add事件，并触发 addFood 事件-->
                  <!--父组件得到通过add过来的子组件的内容event.target,传递给了addFood作为参数-->
                  <cartcontrol @add="addFood" :food="food"></cartcontrol>
                </div>
              </div>

            </li>
          </ul>
        </li>
      </ul>
    </div>
    <!--使用购物车组件 （传参  ）-->
    <shopCart ref="shopcart" :select-foods="selectFoods" :delivery-price="seller.deliveryPrice" :min-price="seller.minPrice"></shopCart>
    <!--父元素监听子元素的add事件，并触发 addFood 事件-->
    <food :food="selectedFood" ref="food" @add="addFood"></food>
  </div>

</template>

<script>
  //引入BScroll库
  import BScroll from 'better-scroll';
  //引入购物车组件
  import shopCart from '../shopCart/shopCart'
  //引入增加和删减的组件
  import cartcontrol from '../cartcontrol/cartcontrol'
//引入单页面的food组件
  import food from '../food/food'
  //定义变量
  const ERR_OK=0;
  export default {
    //接受参数
    props:{
      seller:{
        type:Object
      }
    },
    //提供数据
    data(){
      return {
        //将得到的goods数据存起来
        goods:[],
        //将每个版块的高度存起来(右侧)
        listHeight:[],
        //(左侧) 与右侧联动高度
        scrollY:0,
      //  当前选中的food
        selectedFood:{}
      }
    },
    //计算属性
    computed:{
      //获取右侧边栏滑动的区间索引
      currentIndex(){
        for(let i=0;i<this.listHeight.length;i++){
          let height1=this.listHeight[i];
          let height2=this.listHeight[i+1];
          if(!height2 || (this.scrollY>=height1 && this.scrollY<height2)){
            return i;
          }
        }
        return 0;
      },
      //关联购物车选择的商品
      selectFoods(){
        let foods=[];
        this.goods.forEach((good)=>{
          good.foods.forEach((food)=>{
            if(food.count){
              foods.push(food)
            }
          })
        })
        return foods
      }
    },
    //类似于初始化页面 init
    created(){
      this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee'];
      this.$http.get("/api/goods").then((response)=>{
        response=response.body;
        if(response.errno ==ERR_OK ){
          this.goods=response.data;
          this.$nextTick(()=>{//dom渲染完全执行里面的代码
            //初始化滚动（BScroll库）
            this._initScroll();
          //  计算每次滚动的高度
            this._calculateHeight();
          });
        }
      },(response)=>{
        console.log("goods加载失败")
      })
    },
    //提供方法
    methods:{
      //初始化滚动条
      _initScroll(){
        this.menuScroll=new BScroll(this.$refs.menuWrapper, {
          //初始化默认的事件
          click:true
        });
        this.foodsScroll=new BScroll(this.$refs.foodsWrapper,{
          //初始化默认的事件
          click:true,
          probeType:3 ///?
        });
      //监听滚动
        this.foodsScroll.on('scroll',(pos)=>{
          //abs() 方法可返回数的绝对值。round() 方法可把一个数字舍入为最接近的整数。
          this.scrollY=Math.abs(Math.round(pos.y));
        });
      },
      //计算滚动高度
      _calculateHeight(){
        //找到每个大区块
        let foodList=this.$refs.foodsWrapper.getElementsByClassName("food-list-hook");
        //将每个大区块的高度存在listHeight数组中
        let height=0;
        this.listHeight.push(height);
        for(let i=0;i<foodList.length;i++){
          height+=foodList[i].clientHeight;
          this.listHeight.push(height);
        }
      },
      //点击菜单栏与右侧内容联动
      selectMenu(index,event){
        //兼容pc端
        if(!event._constructed){
          return
        }
        //根据index 索引使右侧内容滚动到对应的高度
        let foodList=this.$refs.foodsWrapper.getElementsByClassName("food-list-hook");
        let el=foodList[index];
      //  滚动开始到对应的位置
        this.foodsScroll.scrollToElement(el,300);
      },
      //父元素触发的addFood事件 给购物车组件的drop的事件传递了target
      //addFood得到子组件传递过来的event.target作为参数进行就算
      addFood(target){
        // 体验优化,异步执行下落动画
        this.$nextTick(() => {
          //将得到的参数继续传递shopcart组件中的给drop方法
          this.$refs.shopcart.drop(target);
        });
      },
    //  点击单个food关联详情页
      selectFood(food,event){
        //兼容pc端
        if(!event._constructed){
          return
        }
        this.selectedFood=food;
        console.log(this.selectedFood);
        this.$refs.food.show();
      }
    },
    //注册组件
    components:{
      shopCart,
      cartcontrol,
      food
    }
  }
</script>

<style lang="stylus" rel="stylesheet/stylus">
  @import "../../common/stylus/index.styl"
  .goods
    display: flex
    position: absolute
    top: 174px
    bottom: 46px
    width: 100%
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          font-weight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          width: 12px
          height: 12px
          margin-right: 2px
          background-size: 12px 12px
          background-repeat: no-repeat
          &.decrease
            bg-image('decrease_3')
          &.discount
            bg-image('discount_3')
          &.guarantee
            bg-image('guarantee_3')
          &.invoice
            bg-image('invoice_3')
          &.special
            bg-image('special_3')
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc
            line-height: 12px
            margin-bottom: 8px
          .extra
            .count
              margin-right: 12px
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px
</style>
